Fig. 2

The co-occurrence network of different metabolites. a The co-occurrence network between 6 and 12 M, b the co-occurrence network between 8 and 12 M. The circle shapes were the different metabolites. The red lines mean the significant positive correlation; the blue lines mean the significant negative correlation. The size of lines mean the correlation size; the size of shapes mean the numbers of networks; the P was positive ion model and the N was negative ion model